The price for a domain is actually what the buyer is willing to pay for. 3,4,5 figures... depends how bad the buyer wants it and how valuable your domain is.
In my case, 99% of my domains are "make an offer". so people can suggest me their price range and I might accept/negotiate the amount.
If you're asking how to appraisal alone by yourself, well, it's pretty hard because in the end of the day the price is how much they buyer is willing to pay for.
But, for example, if you have a 4L.com domain you can estimate the average price you should ask for. Most 4L's selling between mid XXX$ - low XXXX$, so you know to put your price tag between. You also need to take into consideration the letters, if it has unique pattern, chinese premium/not etc..
I hope this helps.